Liquid rheostat.



H. A. STEEN.

LIQUID RHEOSTAT.

APPLICATION FILED 001.23. 1914.

Patented Nov. 30, 1915.

STATES PATENT OFFICE HALFDAN A. STEEN, 0F MILWAUKEE, WISCONSIN, ASSIGNORTO THE CUTLER-HAMMER MFG. (10., OF MILWAUKEE, WISCONSIN A CORPORATION OFWISCONSIN.

LIQUID RHEOSTAT.

Specification of Letters Patent.

Patented Nov. 39, 1915:.

To all whom it may concern.

Be it known that I, HALFDAN A. STEEN, a subject of the King of Norway,residing at Milwaukee, in the county of Milwaukee and State oflVisconsin, have invented new and useful Improvements inLiquidRheostats, of which the following is a full, clear, concise, andexact description, reference being had to the accompanying drawing,forming a part of this specification.

This invention relates to liquid rhcostats. Such rheostats arefrequently employed for accelerating and regulating electric motorswhere, to meetditterent load conditions, they must be adjusted forwidely different resistance values. Heretot'ore such adjustments havebeen effected either. by varying the level of the rheostat fluid or byadjusting the rheostat electrodes.

This invention has among lts ob ects to provide means for more readilyand expeditiously accomplishing the aforesaid results."

A further object is to provide means for the aforesaid purpose whicheliminates the necessity for varying either the fluid level or theposition of the electrodes to efiect wlde resistance adjustment andwhich increases the fineness of subsequent regulation obtainable by suchrelative liquid level variations.

Further objects and advantages will appe' r hereinafter in connectionwith the following description of a typlcal embodiment of the inventionschematically illustrated in the accompanying drawing.

Referring more specifically to thedrawing, there is shown a conventionalform of tank having an upper compartment 1, for the electrodes and alower compartment .2

constituting a reservoir for the water or other liquid which is fed intothe compartment 1 as required, by a pump 3. The compartment 1 has anoutlet 4 communicating with the compartment 2 .and provided withadjustable means 5 for regulating the size thereof to thereby regulatethe level of the liquid circulating in said compartment 1. Also saidoutlet is so positioned as to retain in the compartment 1 at all times apredetermined amount of liquid.

Considering now the electrodes 6 illustrated, the same are adapted to besupported at the desired height in the compartment 1 1n the usual mannerbut they are. unlike the usual electrodes in important respects Whereasthe ordinary electrodes are e1ectri may be readily varied to vary thecurrent carrying area of the individual electrodes and thereby adjustthe resistance value of the rheostat for a given level of liquid.

More specifically, the electrodes illustrated are each divided into twosections a and o of diii'erentsurface areas and said sections arearranged to be included in circuit selectively by a suitable switch 7 orin parallel by said switch 7 and a suitable auxiliary switch 8. Thus theeffective area of each electrode and consequently the total resistanceof the rheostat for a given liquid level may be varied to three values,2'. 0., full effective area with a consequent minimization of resistanceby paralleling the sections a and 6, minimum effective area with aconsequent maximization of resistance by inclusion of only the smallersection b and mean effective area and resistance by inclusion of onlythe larger section (4.

Of course it will be understood that the number and relative sizes ofthe electrode sections may be varied as desired and that such sectionsmay in practice be of any pre ferred shape and size and u'iechanicallyconnected to provide a unitary electrode. Hence t will be apparent thatthe rheostat may be readily designed to meet varying loadv conditionsand readily adjusted by mere variationof connections to meet the widelydifferent conditions as they arise withoutresorting to the timeconsuming and in other respects unsatisfactory.method of adjusting theelectrodes in the. liquid or varying the liquid level with respect tothe electrodes. At the same time,- the adjustment provided by thesectional electrodes also increases the range of subsequent adjustmentattainable by variation of the liquid level, since, as will be apparent,such variation may be effected by raising or lowering the liquid levelfronrmaximum to electrodes is immersed so that comparatively 110generally be 7 I tively including in circuit one or more sections incircuit divided into sections and wide variations in the liquid leveleffect only comparatively small resistance changes.

What I claim as new and desire to secure by Letters Patent is 1. In aliquid rheostat, electrode plates divided into sections and means forconnecting such sections in circuitselectively.

2. In a liquid rheostat, electrode plates divided into sections ofdifferent current carrying area and means for connecting suchselectively.

3. In a liquid rheostat, electrode plates divided into sections andmeans for selec -f such sections.

4. In a liquid rheostat, electrode plates means for selectivelyincluding in circuit all or any one of such sections.

5. In a liquid rheostat, electrode plates leling such sections and. alsomeans for excluding certain of the same from circuit.

6. In a liquid rheostat, electrode plates divided into sections, andmeans for paralleling such sections and also means for excluding any ofthe same from circuit selectively.

7. In a liquid rheostat, electrodes divided into sections of differentcurrent carrying area and means for including in circuit a variablenumber of such sections.

8. In a liquid rheostat, electrodes divided into sections of differentcurrent carrying area and means for including in circuit all of suchsections or any of the same selectively.

divided into sections, and means for paral 9. In a liquid rheostat,electrodes of different capacities arranged in groups and means forparalleling the electrodesof each group and also means for connecting incircuit certain of the same to the exclusion of the remainder.

10. In a liquid rheostat, electrodes of different current capacitiesarranged in groups and means for paralleling the electrodes of eachgroup and also means for connecting in circuit any one of the same tothe exclusion of the remainder. I

11. In a liquid rheostat, in combination, a container, liquid resistortherein, a plurality of electrodes immersed in said resistor, means-forvarying the level of said resistor relative to said electrodes forvarying the resistance value of the rheostat, and means for varying theefi'ective immersed area of said electrodes to vary the amount ofresistance difference efiected by a given variation in the resistorlevel. I

12. In a Water rheostat, in. combination, a plurality of electrodes ofdifi'erent surface areas and means to vary the circuit connectionstherebetween for effecting any given resistance adjustment with aminimum change of Water level and with a minimum length of water line onthe current carrying electrodes.

In Witness whereof, I have hereunto subscribed my name in the presenceof two witnesses.

HALFDAN A. STEEN. lVitnesses:

. L. A. WA'rsoN, TEKLA BAST.

